The general, and at the same time dynamic, type of analysis still remains an unwritten chapter of economic theory, the claims of innumerable “model-b… - Wassily Leontief

Much of current academic teaching and research has been criticized for its lack of relevance, that is, of immediate practical impact... The trouble is caused, however, not by an inadequate selection of targets, but rather by our inability to hit squarely any one of them... The weak and all too slowly growing empirical foundations clearly cannot support the proliferating superstructure of pure, or should I say, speculative economic theory.

How will the cessation of war purchases of planes, guns, tanks, and ships … affect the national level of employment? How many new jobs will be created by the consumers’demand for an additional one million of passenger cars, how many of these jobs can be expected to be located in the automobile industry itself, and how many in other industries such as Steel and the Chemicals, the Coal and the Petroleum industries? How much additional freight traffic and revenue can the American railroads expect to derive from every billion dollars worth spent on post-war housing construction?

By the time it comes to interpretation of the substantive conclusions, the assumptions on which the model has been based are easily forgotten. But it is precisely the empirical validity of these assumptions on which the usefulness of the entire exercise depends... A natural Darwinian feedback operating through selection of academic personnel contributes greatly to the perpetuation of this state of affairs.